VESSEL REVIEW | Grace Darling – Hybrid windfarm support daughtercraft for UK’s North Star

Aberdeen, Scotland-based operator the North Star Group, via its North Star Renewables division, recently took delivery of a new hybrid-powered daughtercraft that will support the maintenance of offshore wind farms in UK waters. The aluminium monohull vessel has been christened Grace Darling in honour of an Englishwoman who is best known for her successful rescue of the stranded survivors of a wrecked merchant ship that was travelling from Hull to Dundee in 1838.

Grace Darling has an LOA of 12 metres, a beam of four metres, a draught of 0.9 metres, a displacement of 12 tonnes, and space for 12 passengers and two crewmembers. Two OXE Marine 223kW outboard engines propel the craft to speeds of just over 18 knots.

The newbuild is the first of four hybrid craft being built by Yarmouth-based Alicat Workboats to a design by Chartwell Marine of Southampton. The daughtercraft will support the safe transfer of in-field wind farm technicians between North Star's larger service operation vehicles (SOVs), where the technicians live while working offshore, to the wind turbines to undertake routine or remedial maintenance. The craft will also be used for trips to and from shore with deliveries.

The hull form, equipment selection, features, and comfort are all focused specifically to suit the demands of offshore wind operations. The design therefore allows transfers to be safely completed to and from offshore wind turbines even in wave heights of 1.7 metres.

To maximise the vessel capability in such wave heights, the design incorporates a high freeboard to allow adequate tunnel clearance to reduce the risk of tunnel slamming. Chartwell Marine said that, during model testing, no slamming was witnessed and the deck was completely dry, regardless of sea state or direction.

The vessel itself is also compatible with a range of commercially available launch and recovery systems (LARS).

Grace Darling and its three sisters will be deployed aboard North Star's SOVs to support operations at the 3.6GW Dogger Bank offshore wind farm in the UK waters of the North Sea. The craft will also perform secondary standby and rescue duties at the same project site.